Connecting my Samsung Smart TV to HH3

I had Infinity installed at home 2 days ago. All is well with download speed, connection to laptops, tablets, smartphones etc., but I have completely lost the ability to connect my Samsung Smart TV to the internet. When I try to connect to the new network, the TV is unable to identify ANY networks, despite the fact that before the BT install, it recognised 5 or 6 from neighbours. I called BT Help yesterday, and after trying a number of things including channel changes, restarting router, TV etc., I got absolutely nowhere. They then put me onto tech support, who said that they'd be able to solve it, but would need to send an engineer to me and charge me! Great customer service!!

Anyway, I am now stuck. I was with Orange previously and the TV connected instantly to my Netgear router without any problems. Does anyone have any suggestions about what I can do to get reconnected?